Fault-block mountains are formed by the movement of large crustal blocks when forces in the Earth's crust pull it apart. Some parts of the Earth are pushed upward and others collapse down.
Fault blocks are very large blocks of rock, sometimes hundreds of kilometers in extent, created by tectonic and localized stresses in the Earth's crust. Large areas of bedrock are broken up into blocks by faults.
The process is simple when forces in the Earth's crust pull it apart.
